My impression of 'California sound' are songs that are perky, catchy, very melodic...A new band from the OC called Jet Set Go, for me, fits the bill. Check out their song "Barcelona" -- I just love the 'sunny-California-cool-vibe'! I think the music video is a blast too! By the way here's the MV: http://www.youtube.com/watch?v=1GYElzjUB2A

Duane Eddy and the Beach Boys. Without them there would be no "California Sound".

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Sorry. I meant Dick Dale, not Duane Eddy. Just got their name's confused.